JP2003528178A - Stable initiator system - Google Patents

Abstract

  (57) [Summary] The acylphosphine initiator used in making the ophthalmic lens is stabilized by adding an acid to the monomer mixture used to make the lens.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION The present invention relates to methods of using photoinitiators. In particular, the present invention relates to the stabilization of photoinitiators useful in each process for making ophthalmic lenses.

Ophthalmic lenses such as contact lenses are often made by methods that employ a photoinitiated polymerization reaction. UV and visible radiation are most often used to initiate curing in these reactions. When it is desirable to prepare a mixture of materials with an initiator or initiator system (where the start comprises more than one component) and other additives that ultimately form the lens upon completion of the above reaction There are many. These types of mixtures are referred to herein as "monomer mixtures (
monomer mix) ". The stability of the initiator can be an important factor in the working time and shelf life of the monomer mixture. That is,
An increase in the working time of this monomer mixture is desirable because it can reduce the need for preparation of starting materials and the possibility of introducing lots into lots and the possibility of changes within the lot during lens manufacturing. Is.

[0003]   Acylphosphines are a type of free that are often used to make ophthalmic lenses.
It is a useful class of initiators of interest in radical polymerization. Many of these materials
The reaction mechanism in Ku is “Reaction Mechanism of Monoacyl-and
・ Bisacyl phoyne oxide photoinitiators study by³¹P
，¹³C-, And¹H-CIDNP and ESR (Reaction Mechanism of Mono
acyl- and Bisacylphoine Oxide Photoinitiators Studied by³¹P,¹³C-, and ¹ H-CIDNP and ESR) ", Urszula Kolczak, Gi
Gunther Rist, Kurt Dietliker
), And Jacob Wirz, 118 Journal American
-Chemical Society (J. Am. Chem. Soc.), P. 6477, (1996
Year). In addition, bisacylphosphines and their uses
US Pat. No. 5,534,559, the usage of which is incorporated herein by reference.
And JP-A-8-259642.

Unfortunately, compounds of this type tend to be unstable in various environments, reducing their potential as active initiators. European Patent No. 849,29
No. 6 proposes a method of stabilizing the bisacylphosphine used in the preparation of urethane (meth) acrylate polymers used in coatings. The method involves mixing each monomer component with this initiator in the presence of a tertiary amine and in the absence of a tin component. In addition, JP-A-4
-6125, JP-A (JP-A) 296315, JP-A (JP-A) 8-1
No. 27630 proposes a similar method for stabilizing monoacylphosphine photoinitiators in the presence of tin compounds used as polymerization catalysts.

Unfortunately, these solutions are undesirable when applied to the monomer mixtures used to make ophthalmic lenses, because they affect various components in the monomer mixtures. This is because of potentially harmful effects that may cause This is especially true when the monomer mixture is used to make silicone hydrogel lenses.

Accordingly, there is a need for new methods for stabilizing acylphosphine initiators.

SUMMARY OF THE INVENTION The present invention is a stable monomer mixture for making ophthalmic lenses. This stable monomer mixture is made by mixing the monomer mixture, the initiator, and the acid.

In another aspect of the invention, a silicone hydrogel monomer formulation is made by mixing a silicone hydrogel forming mixture, an initiator, and an acid.

In yet another aspect of the invention, a method of stabilizing an initiator system comprises reducing the pH of the initiator system.

In yet another aspect of the invention, a method for stabilizing a silicone hydrogel monomer formulation in a mixture of a reactive silicone macromer and a photoinitiator is provided by acidifying the mixture of macromer and photoinitiator. Including mixing.

[0011] Detailed Description of the Invention   The initiator of the present invention is an initiator having the following structure.

[Chemical 7] Structure I In this formula, R ¹ , R ² and R ³ are each independently H or C _1-12 substituted or unsubstituted alkyl, cycloalkyl, or aromatic moieties, and R ¹ , R ² and R 3 ^At least one of the three has the structure:

[Chemical 8] Structure II At this acyl carbon, attached to P above, R ^{4 to} R ⁸ are each independently H or C _1-3 substituted or unsubstituted alkyl or alkoxy moieties.

In each case where R ^{1 to} R ⁸ are substituted, the substituent may comprise a hydroxy or C _1-4 alkyl, alkoxy, alkenyl, or alkynyl group. Substitution with heteroatoms such as nitrogen, sulfur, and halogen atoms is also possible, but not preferred.

Both R ¹ and R ² are preferably moieties of Structure II above with the respective substituents of R ⁴ and R ⁸ . Furthermore, it is most preferred that R ⁴ and R ⁸ are each a methoxy group. In addition, R ³ is more preferably a C _1-10 alkyl, alkoxy, or alkenyl group substituted with a C _1-2 alkyl group, and most preferably a substituted pentyl group. .

In the most preferred embodiment, R ¹ and R ² are both moieties of Structure II above where R ⁴ and R ⁸ are each a methoxy group, and R ¹ is a trimethylpentyl group. Therefore, the most preferred embodiment has the following structure:

[Chemical 9] Structure III

Each of the above initiators can be used alone, or benzoin methyl ether, 1-hydroxycyclohexyl phenyl ketone, Irgacure 18
50 (Irgacure 1850) Trademark Photoinitiator, 1-Hydroxy Cyclohexyl
Phenyl ketone (commercially available as "Irgacure 184"), 2-benzyl-2-n-dimethylamino-1- (4-morpholinophenyl) -i-butanone ("Irgacure 369 (Irgacure 369)". Available on the market), 1-hydroxycyclohexyl phenyl ketone (5
0% by weight) + benzophenone (commercially available as "Irgacure 500"), 4- (2-hydroxyethoxy) phenyl- (2-hydroxypropyl) ketone (as "Irgacure 2959"). Commercially available), 2,4,6-trimethyl benzoyl diphenyl phosphine oxide (TPO) (50% by weight) + 2-hydroxy-2-methyl-1-phenyl-propan-1-one (HMPP) (50 % By weight) (available on the market as "Darocur 4265"), 2,2-dimethoxy-2-phenylacetophenone (BDK) ("Irgacure 651 (Irgacur
cure 651) ”, bis (nl-2,4-cyclopentadien-1-yl), bis (2,6-difluoro-3- (1H-pyrrole-1).
-Yl) phenyl) titanium (CGI-784), 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one (MMMP) ("Irgacure 907)" in the market Available), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (HMPP) (commercially available on the market as "Darocur 1173"), or mixtures thereof and the like. It can be used in combination with an initiator. Preference is given to respective mixtures which comprise UV and visible light initiator systems, which allow a more flexible use of UV blockers in the monomer mixture.

Stabilizers useful in the present invention are acids. These are preferably weak organic acids, but may also include strong organic acids as well as Lewis acids. In addition, precursors capable of generating acid in the reaction mixture can also be used. The most preferred acid is acetic acid,
Formic acid, propionic acid, and acrylic acid.

Examples of the inorganic acid include hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, hydroiodic acid, hydrofluoric acid, sulfurous acid, nitric acid, nitrous acid, phosphorous acid, perchloric acid, chloric acid, Chloric acid, iodic acid, bromic acid, arsenic acid, carbonic acid, selenium hydride, tellurium hydride, phosphonic acid, hypophosphoric acid, diphosphoric acid, pyrophosphoric acid, metaphosphoric acid, polyphosphoric acid, selenic acid, selenious acid,
Includes telluric acid, tellurous acid, arsenous acid, antimony acid, antimony acid, borofluoric acid and the like.

The organic acid is, for example, hydroxymethanesulfonic acid, trifluoromethanesulfonic acid, beta-bromoethanesulfonic acid, allylsulfonic acid, 2-methyl-sulfonic acid.
2-[(1-oxo-2-propenyl) amino] -1-propanesulfonic acid, D
-10-camphorsulfonic acid, benzenesulfonic acid, m-nitrobenzenesulfonic acid, m-benzenedisulfonic acid, methanesulfonic acid, ethanesulfonic acid, 2
-Hydroxyethanesulfonic acid, 2- (cyclohexenylamino) methanesulfonic acid, (3-cyclohexenylamino) methanesulfonic acid, p-ethylbenzenesulfonic acid, alpha-naphthalenesulfonic acid, beta-naphthalenesulfonic acid, p-toluenesulfone Acid, p-chloromethylbenzenesulfonic acid, p-phenolsulfonic acid, 2-pyridylhydroxymethanesulfonic acid, sulfonic acid such as 2,6-naphthalenedisulfonic acid, benzenesulfinic acid, organic sulfinic acid such as p-toluenesulfinic acid , Phenylphosphonous acid, butylphosphonous acid, methylphosphonous acid, dibenzenephosphinic acid, dibutylphosphinic acid, benzenephosphonic acid, methylphosphonic acid, phenylphosphinic acid, methylphosphinic acid, dibenzenethiophosphine Acid, dibutylthiophosphinic acid, benzenethiophosphonic acid, methylthiophosphonic acid, phenylthiophosphinic acid, methylthiophosphinic acid, benzenethiophosphonous acid, dibutylthiophosphonous acid, diethyldithiophosphate, alpha-hydroxybenzylphosphonous acid, toluene Substituted or unsubstituted aliphatic carboxylic acids including organic phosphoric acid such as phosphonic acid are, for example, mandelic acid, acetic acid, lactic acid, ascorbic acid, phenylacetic acid, bromoacetic acid, trichloroacetic acid, chlorodifluoroacetic acid, thioacetic acid, glycol. Acetic acid, glyoxylic acid,
Acrylic acid, beta-chloroacrylic acid, cyanoacetic acid, ethoxyacetic acid, beta-
Chloropropionic acid, perfluoropropionic acid, propiolic acid, n-butyric acid,
Isobutyric acid, alpha-hydroxybutyric acid, crotonic acid, mucochloric acid, cyclopropanecarboxylic acid, isovaleric acid, 1-methylcyclopropanecarboxylic acid, 1-cyanocyclopropanecarboxylic acid, cyclobutanecarboxylic acid, cyclopentanecarboxylic acid, 2 -Ketobutyric acid, levulinic acid, pivalic acid, tert-butylacetic acid, coumaric acid, 3
-Cyclohexenecarboxylic acid, beta-2-furylacrylic acid, 3-pyridylacetic acid, phenylthioacetic acid, m-chlorophenylacetic acid, o-nitrophenylacetic acid, p
-Fluorophenylacetic acid, o-hydroxyphenylacetic acid, phenoxyacetic acid, o-
Chlorophenoxyacetic acid, 2,4-dichlorophenoxyacetic acid, 2,4,5-trichlorophenoxyacetic acid, cyclohexylacetic acid, 1-methyl-1-cyclohexanecarboxylic acid, 6-acetamidohexanoic acid, heptyl acid, dl-tereonic acid, benzoyl Formic acid, cinnamic acid, o-chlorocinnamic acid, 2,4-dichlorocinnamic acid, m-
Nitrocinnamic acid, o-hydroxycinnamic acid, d-2-phenoxypropionic acid,
3-phenoxypropionic acid, 3-phenylpropionic acid, 3- (p-hydroxyphenyl) propionic acid, 2- (2,4,5-trichlorophenoxy) propionic acid, 4-methoxyphenylacetic acid, p-chloro-2- Methylphenylacetic acid, 3
, 4-methylenedioxyphenylacetic acid, 4-chloro-2-methylphenoxyacetic acid, m-tolylacetic acid, alpha, alpha, alpha-trifluoro-m-tolylacetic acid, p-hydroxyphenylpyruvic acid, alpha-cyanocinnamic acid , P-methoxycinnamic acid, m-trifluoromethylcinnamic acid, 3,4-methylenedioxycinnamic acid, 3,4-dimethoxyphenylacetic acid, (-)-alpha-methoxy-alpha-trifluoromethylphenyl Acetic acid, 1,4-benzdioxane-6-acetic acid, 3-phenyl-n-butyric acid, 1-phenyl-1-cyclopropanecarboxylic acid,
2- (p-methoxyphenyl) -acetylene-1-carboxylic acid, 3-benzoylpropionic acid, 2- (p-chlorophenoxy) -2-methylpropionic acid, alpha-naphthylacetic acid, beta-naphthoxyacetic acid, 3,4 , 5-trimethoxyphenylacetic acid, diphenylacetic acid, bis (p-chlorophenyl) acetic acid, 1-menthoxyacetic acid, diphenyleneacetic acid, 1-phenylcyclopentanecarboxylic acid, 1- (p-
Chlorophenyl) -1-cyclopentanecarboxylic acid, dl-3-camphorcarboxylic acid, palmitic acid, stearic acid, benzylic acid, deoxycholic acid, linoleic acid, oleic acid, alpha-acetamidocinnamic acid, etc. Examples of the acid include benzoic acid, salicylic acid, o-toluic acid, alpha, alpha,
Alpha-trifluoro-m-toluic acid, p-ethylbenzoic acid, 2,6-dimethylbenzoic acid, 2,4,6-trimethylbenzoic acid, p-tert-butylbenzoic acid,
p-Bromomethylbenzoic acid, 2-biphenylcarboxylic acid, 4,4'-methylenebis (3-hydroxy-beta-naphthoic acid), alpha-naphthoic acid, p-benzoylbenzoic acid, phthalamic acid, o-phthalaldehyde acid, m -Nitrobenzoic acid, 3,4-dinitrobenzoic acid, m-cyanobenzoic acid, thiosalicylic acid, gallic acid, m-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 1-hydroxy-2-naphthoic acid, o- Anisic acid, 3,4-dimethoxybenzoic acid, 4-hydroxy-3-methoxybenzoic acid, 4-hydroxy-3,5-dimethoxybenzoic acid, 4
-N-butoxybenzoic acid, 3-phenoxybenzoic acid, piperonyl acid, o-acetamidobenzoic acid, p-chlorobenzoic acid, 3,5-dichlorobenzoic acid, o-fluorobenzoic acid, m-fluorobenzoic acid, 2, 6-difluorobenzoic acid, 2,6-dichlorobenzoic acid, 2,3,5-triiodobenzoic acid, 4-chlorosalicylic acid, 3
-Nitrosalicylic acid, 5-bromosalicylic acid, 2-chloro-3-nitrobenzoic acid, 3-chloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 3-chloro-4-methylbenzoic acid , 3-methoxy-4-nitrobenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3-methoxy-4-methylbenzoic acid, 3-methyl-2-nitrobenzoic acid, 3-hydroxy-4-nitrobenzoic acid Three
, 5-di-tert-butyl-4-hydroxybenzoic acid, o-thymotic acid and the like,
Heteroaromatic carboxylic acids are, for example, N-methylpyrrole-2-carboxylic acid, 2
-Furancarboxylic acid, 5-bromo-2-furancarboxylic acid, pyrrole-2-carboxylic acid, 3-furancarboxylic acid, nicotinic acid, isonicotinic acid, citrazinic acid,
Substituted or unsubstituted aliphatic polycarboxylic acid, including alpha-picolinic acid and the like,
For example, succinic acid, fumaric acid, maleic acid, malic acid, tartaric acid, citric acid, oxalic acid, malonic acid, ethylmalonic acid, hydroxymalonic acid, methylsuccinic acid, 2-
Methyl-2-phenylsuccinic acid, 2-ethyl-2-methylsuccinic acid, 2-isopropylsuccinic acid, bromosuccinic acid, 2,3-dibromosuccinic acid, alpha-ketoglutaric acid, 3-ethyl-3-methylglutaric acid, glutacon Acid, itaconic acid,
Including mesaconic acid, citraconic acid, adipic acid, camphoric acid, diglycolic acid, acetylenedicarboxylic acid, dimethylcyclopropanedicarboxylic acid, etc., and aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, -Nitrophthalic acid, 4-hydroxyisophthalic acid, tetrachlorophthalic acid,
It includes tetrachloroterephthalic acid, nitroterephthalic acid, pyrazine-2,3-dicarboxylic acid, o-phenylenediacetic acid, 5,5'-methylenedisalicylic acid, and the like. Phenol includes, for example, picric acid and 2,4-dinitrophenol. 2,6-dinitrophenol, 2,6-diiodo-4-nitrophenol, 2,6-dichloro-
4-nitrophenol, 2,5-dichloro-4-nitrophenol, 2,6-dibromo-4-nitrophenol, 2-bromo-4-chloro-6-nitrophenol, 2,4-dichloro-6-nitrophenol And the like, and substituted or unsubstituted dithiocarbamic acid is, for example, 2-cyclohexenyldithiocarbamic acid, 2-cyclohexenyldithiocarbamic acid,
It includes cycloheptenyl dithiocarbamic acid, methyldithiocarbamic acid, dimethyldithiocarbamic acid, ethylene bis (dithiocarbamic acid) and the like.

Examples of the Lewis acid include boron trifluoride, boron trichloride, boron tribromide, aluminum fluoride, aluminum chloride, aluminum bromide, aluminum iodide, aluminum sulfate, iron fluoride, iron chloride and bromide. Iron, iron nitrate, iron sulfate, gallium fluoride, gallium chloride, antimony fluoride, antimony chloride, antimony sulfate, iridium fluoride, iridium chloride, tin fluoride, tin chloride, tin bromide, tin iodide, arsenic fluoride , Arsenic chloride, zinc fluoride, zinc chloride, zinc bromide, zinc iodide, copper chloride, barium chloride, silver chloride and the like.

It is generally desirable for the acid used in the practice of this invention to be at a molar concentration or concentration such that the monomer mixture is used at pH 3-8. Preferably,
This pH value is lower than 7. Even if the upper limit of the pH value at which the monomer mixture can be lowered is slightly alkaline, the pH value is lowered by the addition of the acid, and this pH value is maintained when the acid is not added. In either case, in the case of a monobasic acid such as HCL (hydrochloric acid), about 0.1% to about 10% by weight of acid is used in the monomer mixture. Based on this, one of skill in the art can readily determine equivalent ranges for other acids that are useful in the practice of the present invention.

The lenses of the present invention are prepared by mixing the components of the above monomer mixture with the above initiators and stabilizers according to well known methods of lens formation such as photoinitiated injection molding in a lens mold. Performed by.

Silicone hydrogels have a high oxygen permeability that is particularly desirable for use in the lenses of the present invention. Where the monomer mixture contains the ingredients for the preparation of the silicone hydrogel, it is referred to herein as the silicone hydrogel forming mixture. Silicone hydrogels are preferably prepared by polymerizing a mixture containing at least one silicone-containing monomer and at least one hydrophilic monomer. Whether any of these silicone-containing or hydrophilic monomers can function as a crosslinker,
Alternatively, another crosslinker can be employed. These cross-linking agents are monomers having a large number of polymerizable sites. The term "monomer", when used in this sense, refers to the material used in forming the final polymer system. The crosslinker can be a monomer, dimer, trimer, or high molecular weight molecule, and can also be considered a monomer for the silicone hydrogel ultimately produced therefrom. The polymerizable functionalities described above generally bind to more than one polymer to form a network or macromolecule-like structure. There are numerous silicone-containing monomeric units commonly used in the formation of such silicone hydrogels. US Patent No. 4
, 136,250, 4,153,641, 4,740,533,
No. 5,034,461, No. 5,070,215, No. 5,260,00
No. 0, No. 5,310,779, and No. 5,358,995 provide some useful examples, each of which is incorporated herein by reference.

Hydrophilic monomers that have already been found to be useful for making silicone hydrogels are unsaturated carboxylic acids such as methacrylic acid and acrylic acid, 2-
Acrylic-substituted alcohols such as hydroxyethyl methacrylate and 2-hydroxyethyl acrylate, vinyl lactams such as N-vinyl pyrrolidone,
And acrylamides such as methacrylamide and N, N-dimethylacrylamide. Yet another example is the hydrophilic vinyl carbonate or vinyl carbonate monomer disclosed in US Pat. No. 5,070,215,
And hydrophilic oxazolone monomers disclosed in US Pat. No. 4,910,277.

Preferred components of the monomer mixture used to make the silicone hydrogel lenses of the present invention include, for example, siloxane and acrylic / methacrylic acid and their derivatives, polyvinyl, generally diethylene glycol, triethylene. Di- of ethylene glycol, butylene glycol and hexane-1,6-diol
Or di- or tri-vinyl monomers, such as tri (meth) acrylate, and divinylbenzene. In a preferred embodiment, the siloxane component is polydimethylsiloxane. The siloxane component is mixed with a hydrophilic monomer such as hydroxyethyl methacrylate or a derivative of acrylate. In the most preferred embodiment, the monomers are mono-alkyl terminated polydimethylsiloxanes (“mPDMS”) such as monomethacryloxypropyl-terminated polydimethylsiloxane and 2-hydroxyethyl methacrylate, methyl methacrylate, methacryloxypropyl. Tris (trimethylsiloxy)
Includes macromers including the reaction product of silane, mono-methacryloxypropyl terminated mono-butyl terminated polydimethylsiloxane, and 3-isopropenyl-α, α-dimethylbenzyl isocyanate. In addition, preferred monomers are, for example, methacryloxypropyltris (trimethylsiloxy) silane or "
TRIS ", N, N-dimethyl acrylamide or" DMA ", triethylene glycol dimethacrylate or" TEGDMA ". In addition, other monomers and crosslinkers known in the art for making silicone hydrogels can be used.

The use of the above mPDMS is notable because the component has a reduced modulus and tan δ (loss of material divided by modulus) without compromising the compatibility of the monomers during the polymerization process. It is believed to be responsible for imparting improved mechanical properties such as elastic modulus or G "/ G ') to the resulting hydrogel. Unlike many siloxanes that are currently predominantly used, mPDMS has no polar functionality and has a relatively high molecular weight, so measurements that improve this incorporation are preferred.The structure of this mPDMS is shown below. You can

[Chemical 10] In this formula, b = 0-100 and R ₅₇ is any C _1-10 aliphatic or aromatic group, which may contain heteroatoms, in which case R ₅₇ is Not functionalized where bonded to Si. A _C3-8 alkyl group is preferred, and a butyl group, particularly a sec-butyl group, is most preferred. R ₅₆ is also any single polymerizable vinyl group. Preferably, this group is a methacrylic moiety, but can be an acrylic or styrene moiety or other similar moiety.

The monomer mixture also includes the above initiator and acid. These can be added before, during, or after the mixture is put into a lens mold or other container for lens molding.

It is also desirable to carry out the above curing in the presence of a diluent. Suitable diluents are alkanols, N, N-dimethylformamide, acetamide, acetonitrile, N, N-dimethylacetamide, heptane, dimethyl sulfoxide, acetone, tert-butyl acetate, ethyl acetate, isopropyl acetate, and N-. Contains methyl-2-pyrrolidone. Low molecular weight (C _5-12 ) alkanols are preferred. Furthermore, dimethyl-3-octanol is most preferred.

[0028]   The invention is further described in the following non-limiting examples.

Example 1 (Formation of Macromer) 13.75 ml of a 1 M solution of TBACB in THF, 30.0 g of bis (dimethylamino) methylsilane, 61.39 in 4399.78 g of THF.
g of p-xylene, 154.28 g of methyl methacrylate and 1892.
To a solution of 13 g of 2- (trimethylsiloxy) ethyl methacrylate, 14 ° C
In, under an atmosphere of N _2, 1-trimethylsiloxy of 191.75G - plus-methoxy-2-methyl propene. Then additional TBACB in THF
30 ml (0.40 M) of was added over a period of 260 minutes, during which time the reaction mixture spontaneously exothermed before cooling to 30 ° C. 60 minutes after the addition of 2- (trimethylsiloxy) ethyl methacrylate, 467.56 g of 2- (
A solution of trimethylsiloxy) ethyl methacrylate, 3636.6 g PDMS and 3673.84 g TRIS and 20.0 g bis (dimethylamino) methylsilane was added and the mixture was allowed to spontaneously exotherm at 30 for 2 hours.
Cooled to ° C. Next, 10.0 g of bis (dimethylamino) methylsilane, 15
A solution of 4.26 g of methyl methacrylate and 1892.13 g of 2- (trimethylsiloxy) ethyl methacrylate was added and the mixture was allowed to exotherm again. After 2 hours, 2 gallons of anhydrous THF was added and the solution was allowed to cool to 34 ° C. before adding a solution of 439.69 g water, 740.6 g methanol and 8.8 g dichloroacetic acid. The mixture was refluxed for 4.5 hours and heated in an oil bath at 110 ° C. to remove each water by adding toluene until water vapor temperature of 110 ° C. was reached while adding each toluene at 135 ° C. Distilled.

The reaction flask was cooled to 110 ° C. and a solution of 443 g TMI and 5.7 g dibutyltin dilaurate was added. The mixture was reacted for 3.5 hours and then cooled to 30 ° C. Then, toluene was evaporated under reduced pressure to obtain a white anhydrous and waxy reactive macromer. The theoretical OH content of this macromer is 1.69 mmol / g.

Example 2 (Lens Formation) The hydrogel was mixed with the following monomer mixture (all amounts are calculated as wt% values in the total weight of the mixture): macromer of Example 1 (-18%).
Si _7-9 monomethacryloxy terminated polydimethyl siloxane (~ 28%), methacryloxypropyl tris (trimethylsiloxy) silane or "TRIS
(~ 14%), dimethylamide or "DMA" (~ 26%), hydroxyethyl methacrylic acid "HEMA" (~ 5%), triethylene glycol dimethacrylate "TEGDMA" (~ 1%), polyvinylpyrrolidone "PVP" (
~ 5%), CGI 1850 (1: 1 (by weight) mixture of 1-hydroxycyclohexyl phenyl ketone and bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylphenyl phosphine oxide) Initiator (~ 1%), glacial acetic acid (
˜5%), and a balanced amount of material with small amounts of additives. Then 20
Polymerization was carried out in the presence of a diluent of wt% dimethyl-3-octanol.

Each hydrogel was cured for 1200 seconds by adding about 0.10 g of the monomer mixture to each cavity of an eight cavity lens mold of the type described in US Pat. No. 4,640,489. Formed by. After that, polymerization was carried out under a nitrogen purge, and 420PS10-25 AM manufactured by Andover Corp.
Photo-initiated by 5 mW cm ^-2 UV light generated by the 39565-02 light filter.

Each lens was then made with the monomer mixture for 5 days without reconstitution of the macromer or other components in the monomer mixture.

This example shows the long processing times that can be achieved by stabilizing the initiator according to the invention.

Example 3 (Comparative Example-No Acid) Example 2 was repeated without acetic acid in the monomer mixture. Lenses could only be made 10 hours before the monomer mixture needed reconstitution due to loss of activity of its initiator.

Examples 4-8 (Stability Studies) Each solution containing 0.8% CGI 1850 and various reagents was diluted with 3-fold diluent.
Prepared in methyl-3-pentanol. UV visualization detection of each sample (
The presence of DMBAPO was determined over time by analysis by reverse phase high performance liquid chromatography with Uv-Vis detection). The results are shown in Table 1.

[Table 1]

Examples 9 to 17 (Stability study in the presence of macromer) 10% by weight of the macromer described in Example 1, 0.1% by weight DMBA.
A solution containing PO and various concentrations of the acids shown in Table 2 was added to the 2-
Prepared in propanol.

[Table 2]

Example 19 The procedure of Examples 10 to 18 above was adopted with the exception of storage at 45 ° C., with the results shown in Table 3.

[Table 3]

Example 24 (Investigation of DMBAPO Stability in Monomer Mixtures Containing Macromers) Each monomer mixture of the type described in Example 2 (Lens formation) was prepared. Mixture 1 contains no acid additives. Mixture 2 contained 0.1% by weight concentrated hydrochloric acid (37% by weight or 10.15M) and Mixture 3 was 1.
It contains 0% by weight glacial acetic acid. Each sample was incubated at 45 ° C. and then analyzed by reverse phase high performance liquid chromatography with UV visualization detection to determine the presence of DMBAPO over time. The results are shown in Table 4.

[Table 4]

Again, it was found that maintaining the pH value of the initiator solution between about 3 and 8 on the stability of DMBAPO resulted.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Vanderran Douglas Gee             32211 Florida, The United States             Jacksonville, Park Ridge Circle             South 8114 (72) Inventor Love Robert N             32216 Florida, United States             Jacksonville, Apartment 3, D             Le Camino Road 1748 (72) Inventor Ford James Dee             United States, 32003 Florida, Oh             Range Park, Nassau Court 515 (72) Inventor Ali Asam             32256 Florida, United States             Jacksonville, Apartment 221, Sa             Usside Building 7816 (72) Inventor Wood Joe M             32205 Florida, United States             Jacksonville, Edgewood Avenue             ー South 1888 (72) Inventor Nanzu Ivan Em             24018 Virginia, United States of America,             Roanoke, Bridlewood Dry             Bu Southwest 5934 F-term (reference) 4J011 QA02 QA17 QA39 QB25 SA84                       TA09 UA01 VA04 WA07                 4J027 AF05 BA06 BA13 BA20 CA21                       CA24 CB10 CC05 CD04

Claims (17)

[Claims] 1. A silicone hydrogel monomer blend comprising: (a) a mixture for forming a silicone hydrogel; (b) an initiator having the structure: Structure I In this formula, R ¹ , R ² and R ³ are each independently H or C _1-12 substituted or unsubstituted alkyl, cycloalkyl, or aromatic moieties, and R ¹ , R ² and R 3 ^At least one of the three has the following structure: Structure II In this formula, R ^{4 to} R ⁸ are each independently a H or C _1-3 substituted or unsubstituted alkyl or alkoxy moiety, and are prepared by adding (c) an acid. Compound. 2. The formulation of claim 1, wherein the acid is selected from the group consisting of Bronsted acids, Lewis acids, and mixtures thereof. 3. The formulation of claim 1, wherein the acid is a weak organic acid. 4. The formulation according to claim 1, wherein the acid is acetic acid. 5. A formulation according to claim 1, which contains from 1 to 100 equivalents of acid per mole of initiator. 6. The formulation of claim 1, wherein the acid is an inorganic acid. 7. A method of stabilizing an initiator system comprising the step of lowering the pH value of the system, wherein the initiator system contains a compound having the structure: [Chemical 3] Structure I In this formula, R ¹ , R ² and R ³ are each independently H or C _1-12 substituted or unsubstituted alkyl, cycloalkyl, or aromatic moieties, and R ¹ , R ² and R 3 ^At least one of the three has the following structure: Structure II In this formula, R ^{4 to} R ⁸ are each independently H or C _1-3 substituted or unsubstituted alkyl or alkoxy moieties. 8. The method according to claim 7, wherein the pH value is reduced to 8 or less. 9. The method according to claim 7, wherein the pH value is lowered by mixing an acid. 10. The method according to claim 7, wherein the pH value is lowered by mixing elements of the group consisting of Bronsted acids, Lewis acids, and mixtures thereof. 11. The method of claim 7, wherein 0.1% to 10% by weight of acid is mixed into the initiator system containing the monomer mixture. 12. A method for stabilizing a silicone hydrogel monomer containing a mixture of a reactive silicone macromer and a photoinitiator having the structure: Structure I In this formula, R ¹ , R ² and R ³ are each independently H or C _1-12 substituted or unsubstituted alkyl, cycloalkyl, or aromatic moieties, and R ¹ , R ² and R 3 ^At least one of the three has the following structure: Structure II In this formula, R ^{4 to} R ⁸ are each independently a H or C _1-3 substituted or unsubstituted alkyl or alkoxy moiety, and the method comprises mixing an acid into the formulation. 13. The method of claim 12, wherein 0.1 wt% to 10 wt% acid is mixed with the initiator system and macromer containing the monomer mixture. 14. The method of claim 12, wherein the acid is selected from the group consisting of Bronsted acids, Lewis acids, and mixtures thereof. 15. The method of claim 12, wherein the acid is a weak organic acid. 16. The method of claim 12, wherein the acid is acetic acid. 17. The method of claim 12, wherein the acid is composed of a solution of at least 0.25% by weight acetic acid.